The invention relates to CATV systems, and more particularly, to CATV systems in which one or more programs are additionally supplied at a premium over those programs generally supplied.
CATV systems are known which provide various channels containing television programs for selective viewing by subscribers to the system. Of these various channels, one or more may be designated as premium channels for selective viewing by those subscribers who pay an additional amount for the privilege of viewing the programs on the premium channels. These programs may be in the form of first run movies, major sporting events, etc. Generally, these programs are scrambled at the cable supplier's head-end and subsequently descrambled at the paying subscriber's home in a device commonly referred to as a set-top converter.
The above type CATV systems have the drawback that when a paying subscriber defaults in his/her payments, access to that subscriber's home must be had in order to disable the descrambler thereby denying that subscriber access to the premium channels.
Moreover, since the descrambling is performed in equipment located inside the subscriber's home, these systems do not address themselves to the use of "bootleg" descramblers which are increasingly finding their way into the marketplace.
In addition, since the scrambling of the programs on the premium channels is effected from the head end of the system, the setting of the descrambler in each of the paying subscriber's homes must be very precise in order to assure satisfactory reception of the desired program.
Finally, these systems do not allow a subscriber having a "cable ready" television receiver to use the various tuning features of the receiver since the set top converter containing the descrambler performs all the tuning functions and provides, for the television receiver, the selected program on a single channel.